Treshnish Isles Auk Ringing Group Report for 2017 Surveyor and the surveyed (Andrew Carter) Compiled by Robin M. Ward Expedition dates: 24th June – 1st July 2017 Expedition members: Robin Ward (Leader), Lila Buckingham, Claire Dovey Andrew Carter, Tim Dixon, George Henderson, Chris Heward, & Shaun Micklewright Correspondence: Robin Ward, 15 Church Close, Great Stukeley, Cambridgeshire, PE28 4AP e-mail: [email protected] CONTENTS Introduction ......................................................................................................................................................... 3 Map of the Treshnish Isles.................................................................................................................................. 4 Weather .............................................................................................................................................................. 5 Systematic List of Birds for 2017 ........................................................................................................................ 6 Systematic List of Mammals for 2017 ............................................................................................................... 13 Systematic List of Lepidoptera for 2017 ........................................................................................................... 15 Other Notable Wildlife Records ........................................................................................................................ 15 Map of census zones ........................................................................................................................................ 16 2017 Breeding Seabird Census Data for Lunga and Sgeir a’ Chaisteil ........................................................... 17 Population Changes for a Selection of Breeding Species on Lunga, 1994 – 2017 ......................................... 19 Treshnish Ringing Totals for 2017 .................................................................................................................... 21 Retrapping Adults for Survival Project .............................................................................................................. 22 Treshnish Ringing Totals 1971 - 2017 .............................................................................................................. 27 Recent Ringing Recoveries .............................................................................................................................. 29 References ....................................................................................................................................................... 31 Acknowledgements ........................................................................................................................................... 32 The Expeditions 1971 – 2017 ........................................................................................................................... 33 Ring Series used on the Treshnish Isles since 1927 ....................................................................................... 36 TIARG Annual Report 2017 v12/01/18 2 INTRODUCTION Since 1971, the Treshnish Isles Auk Ringing Group (TIARG) has monitored, through ringing and census work, the breeding seabird populations of the Treshnish Isles, Argyll. A summary of the early expeditions is given in Birds on the Treshnish Isles 1971-1995 (Walker & Cooper 1996). Annual reports have been produced since 1996. This report summarises the results of the Group’s 39th expedition to the Treshnish Isles, during 24th June – 1st July 2016. As in previous years, the expedition was based around the village ruins at the northern end of Lunga. The majority of the week’s fieldwork was centred upon Lunga and Sgeir a’ Chaisteil where the annual full seabird census and ringing of specific seabird colonies was carried out. Use of the inflatable boat kindly loaned by the Hebridean Trust, enabled seabird census coverage of the islands between Lunga and Fladda, including Fladda. Bac Mór and Bac Beag were surveyed from boat (Hoy Lass, Turus Mara) for the first occasion since 2011. This year was the twelfth year of a Shag Retrap Adult Survival study (RAS); this entails ringing each adult with its own uniquely engraved colour-ring so that it can be re-identified in the field in future years. This is part of the British Trust for Ornithology’s (BTO) Integrated Population Monitoring Programme, funded by the UK Government. The Group’s activities were dictated as always by the prevailing weather conditions. The frequent occurrence of rain showers and a breeze at night, limited the extent of mist netting of Storm Petrels achieved on Lunga as part of the Group’s two Storm Petrel RAS studies. All TIARG census and ringing data are submitted to two national monitoring programmes, the Seabird Monitoring Programme (JNCC) and National Ringing Database (BTO), respectively. The data supplied are of great conservation value, being the sole means of monitoring the seabird colonies of the Treshnish Isles. The conservation importance of these islands is recognised by their designation by the UK Government as a Special Protection Area for internationally important populations of breeding Storm Petrel Hydrobates pelagicus and wintering Barnacle Geese Branta leucopsis. The islands have also been designated a Site of Special Scientific Interest (SSSI) for seabird breeding colonies of national importance. Financial support for the monitoring work TIARG undertook in 2017 was provided by the Hebridean Trust (www.hebrideantrust.org), owners of the islands. Expedition participants 2017: (left to right back row) Robin Ward, Shaun Micklewright, Andrew Carter, (left to right front row) Chris Heward, George Henderson, Claire Dovey, Tim Dixon & Lila Buckingham (Andrew Carter) TIARG Annual Report 2017 v12/01/18 3 MAP OF THE TRESHNISH ISLES Positioned approximately 2.5 miles south west of Lunga TIARG Annual Report 2017 v12/01/18 4 WEATHER Max Wind Gust Gust Max Wind Wind Direction Direction Wind Average Wind Wind Average speed (mph) (mph) speed Cloud cover cover Cloud Temp ( Temp Pressure Pressure Visibility Visibility (oktas) (oktas) (miles) (miles) (mph) (mph) RH % % RH (hPa) (hPa) Notes - Date Time Significant weather during the C) C) day 24.06.2017 21:30 31 18 WSW 11 78 997 7 29 Evening sunshine 25.06.2017 08:00 27 17 WNW 11.5 86 998 8 18 Showers 17:00 18 14 NW 13.5 86 1001 5 29 Showers 22:30 13 10 NW 12 89 1003 4 29 26.06.2017 03:30 5 3 NW 11.3 90 1008 3 29 Calm 09:30 4 3 W 13 83 1009 7 29 calm 15:00 - 15 Breeze picking up 17:00 5 2.5 N 17 72 1009 7 50 Heavy sky 27.06.2017 03:00 12 10 ESE 13 79 1005 8 18 06:30 7 4 SE 12 100 1002 8 1 Continuous rain, cleared 06.45 10:00 20 14 SE 13 93.5 1001 8 29 Light rain 13:00 12 10 SE 13 91 1001 8 50 Dry 28.06.2017 02:30 - - Woken by continuous rain 05:00 - - Still raining 11:00 8 7 SE 15 80 1000 3 50 Sunshine 19:00 11 9 NW 14 89 1000 8 50 29.06.2017 07:30 19 15 NNW 11 78 1000 8 29 High blanket cloud 10:30 21 14 N 12 83 1001 8 18 High blanket cloud 15:30 18 12 N 12 86 1001 8 18 Light rain 16:30 22 16 NNW 12 95 1001 8 18 Rain 23:00 23 16 NW 11 100 1002 8 5 Rain 30.06.2017 08:00 17 12 NW 12 1005 8 18 16:00 16 12 NW 13 95 1008 8 6 Sunshine 22:00 12 7 W 12 96 1010 1 29 Clear sky 01.07.2017 06:00 - SW - Light wind - calm 10:30 14 7 E 14 99 1007 1 18 Showers during morning Meteorological data tabulated above was recorded using a hand-held weather station on Lunga during the period 24 June to 1 July 2017. George Henderson TIARG Annual Report 2017 v12/01/18 5 SYSTEMATIC LIST OF BIRDS FOR 2017 The following systematic list describes those bird species seen during the Treshnish Isles Auk Ringing Group’s presence on the Treshnish Isles, 24thJune – 1st July 2017. The introductory comments (first paragraph) refer to the species’ status during the breeding season as recorded by previous expeditions. A detailed breakdown of breeding seabird numbers on Lunga and Sgeir a’ Chaisteil in 2017 is provided on page 17. Greylag Goose Anser anser Breeding noted in some years, with a moulting flock present during late summer. The moult flock had built up to at least 98 birds by 28th June, typically most were around the islands of Sgeir an Eirionnaich, Fladda and Sgeir an Fheòir. At least 32 and 12 birds were seen on Bac Mór and Bac Beag respectively during a boat-based survey on 30th June. Year 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Peak 25 160 240 268 79 101 316 90 164 77 count Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Peak 80 225 160 140 50 140 196 272 70 98 count Canada Goose Branta canadensis Rare visitor. Two birds were seen with Greylag Geese on Sgeir an Eirionnaich on 25th, 26th and 28th June. These sightings represent the second record by TIARG of the species on the Treshnish Isles, the previous record in 2016. Shelduck Tadorna tadorna Until recently a rare visitor with one pair having bred occasionally since 2003. There were no records of this species. Eider Somateria mollissima Breeds regularly in small numbers. Two broods were noted at Lunga’s north end, one duck with three ducklings and one duck with a single duckling. Elsewhere a duck with three ducklings were seen at Tarbet, Lunga. The only males recorded were up to two late-summer moulting birds in the waters between Fladda and Lunga, and a single bird off Little Dutchman. Red-breasted Merganser Mergus serrator Rare visitor. One male were seen in flight from the Village,